Proteolytic enzymes isolated from either bacteria or host tissues have been shown by others to act directly on soluble collagen or human C'5 resulting in the production of fragments chemotactically active toward neutrophils. Thus, it seems likely that mechanisms independent of antibody and/or complement exist for initiating inflammation. In the light of the above published observations, we propose to determine whether proteases isolated from selected oral bacteria (Streptococcus mutans, S. sanguis, Actinomyces viscosus, A. naeslundii, Fusobacterium nucleatum, Veillonella alcalescens, and Candida albicans) are, in fact, capable of generating chemotactic fragments from (1) proteins derived from gingival sulcular bacterial species, (2) non-chemotactic proteins commonly found in gingival tissue such as serum albumin, elastin, and collagen, and (3) perhaps purified human C'3 and C'5. Extra- and intra-cellular bacterial proteases will be purified and some of their relevant characteristics (such as optimal assay conditions, inhibitors etc.) determined. Rabbit neutrophil chemotaxis assays will be performed in the absence of serum in chambers similar to the Boyden design. The results of this study may establish whether oral bacterial proteases have the potential to contribute to the initiation of inflammation in the human gingiva. BIBLIOGRAPHIC REFERENCE: Germaine, G.R. and C.F. Schachtele. 1976. Streptococcus mutans Dextransucrase: Mode of Interaction with High Molecular Weight Dextran and Role in Cellular Aggregation. Infec. Immun. 13 (in press).